<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
    <style>
        html *{
            padding: 0;
            margin: 0;
        }
    </style>
</head>
<body>
    <!-- BFC不与float重叠 -->
    <section id="layout">
    <style>
        #layout {
            background: red;
        }
        #layout .left {
            float: left;
            width: 100px;
            height: 100px;
            background: pink;
        }
        #layout .right {
            height: 110px;
            background: #ccc;
        }
    </style>
    <!--左边宽度固定，右边自适应-->
    <div class="left">左</div>
    <div class="right">右</div>
    </section>

    <section id="float">
        <style>
            #float .float {
                float: left;
                font-size: 30px;
            }
        </style>
        <div class="float">woshifudongyuanso</div>
    </section>
</body>
</html>